1. Technical Field
This invention relates to rods and, more particularly, to a reinforcing rod for use in continuously reinforced concrete pavement.
2. Prior Art
The present invention pertains to improvements in the field of pavement construction such as those designed for highway transportation. It is well known that concrete has a comparatively high compressive strength, a comparatively low tensile and shear strength, and that concrete expands and contracts due to changes in temperature. Because highways can experience large temperature changes over the course of a calendar year, accommodations must be made for the resulting changes in the concrete.
For example, winter temperatures may cause the concrete to experience subzero temperatures, while the same concrete may be exposed to temperatures of over 100 degrees Fahrenheit in the summer. The thermal expansion and contraction of the concrete under these conditions can prove destructive, leading to cracking and surface discontinuities if the proper precautions and measures are not taken. In addition concrete will crack naturally, as a result of the curing process, which takes place from the time of placement of the fluid concrete material, until full design strength is achieved. This occurs usually within one month after initial placement of the concrete.
Engineers have found that a series of concrete blocks or slabs positioned with a gap to relieve the stresses in the blocks at the maximum expansion anticipated provides the best solution to these problems. Joints or spacing in between the blocks are necessary to accommodate thermal expansion and contraction of the concrete due to changes in the environmental temperatures, and strategic placement of the joints assist engineers in controlling the direction of the expansion and predicting the location where the concrete will crack as a result of the curing process.
The use of discrete blocks, however, is not without its own problems. Uneven expansion or contraction of the individual blocks can result in discontinuities in the highway which, in turn, can lead to unsatisfactory road conditions as well as stress and fatigue in the individual blocks. Blocks can shift up to create unsafe road conditions and reduce the life of the road
Accordingly, a need remains for a reinforcing rod in order to overcome the above-noted shortcomings. The present invention satisfies such a need by providing a reinforcing rod that is easy to install and improves the durability of the concrete it is employed with. By aligning the non-deformed sections of a series of parallel rods of this nature, the hairline cracks that develop in the subsequently applied concrete will form transversely and with uniform spacing therebetween. This helps to extend the overall life expectancy of the roadway in question.